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rob.onions
New Member
United Kingdom
29 Posts |
 Posted - 22/03/2008 : 10:43:45
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| The km interval is coming up for checking the balance of the carbs on my 92SF. My generic manual says that you just pop the guage tubes onto the outlet ports (think I have found them) The (broken english) translated Russian CD manual that I have for the SF says you need a T-joint that connects number 1 carb to one of the fuel tubes (but I'm not really sure which one it is suggesting. This seems the more complicated option. Can anyone give a difinitive method of checking SF carbs? Thanks |
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rob.onions
New Member
United Kingdom
29 Posts |
Posted - 22/03/2008 : 11:04:55
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| Another question to add to my first. The ports to which you attach the vacuum tubes - are they underneath the carbs pointing just slightly forwards (fairly easy to get to without any tank removal) or is that just wishful thinking and I am actually looking at the wrong things. What I think are the vacuuum ports have no kind of caps like the manual suggests. |
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alexibrow
Settled In Member
United Kingdom
64 Posts |
Posted - 23/03/2008 : 21:25:11
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STOP! Before you adjust anything, have you run anything through the carbs to get rid of any fuel deposits that may be sticking to needles, jets etc? I ran a few tanks of Shell Optimax through mine a while ago and got an immediate increase in power. The cheaper fuels lack the detergents of the premium ones, and if you use the cheap stuff all the time the carbs will get bunged up with unwanted stuff.
As the deposits build up, the carbs slowly go out of tune. Rebalancing them is one option, or you could just remove the deposits instead... Of course, if the carbs have been retuned at all in the past, then you'll need to tune them back to where they were to start with!
A friend of mine recommended Injection Correction, which I have yet to try, as the Optimax seemed to do the trick. I intend to use it at some point, and I'll post my observations when I do.
Let us know how you get on, whether you decide to follow my advice or not!
Al. |
It's not karma, its bikema. |
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rob.onions
New Member
United Kingdom
29 Posts |
Posted - 24/03/2008 : 20:20:55
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Thanks for the advice Al, I think I'll give it a go. How much does it cost? So, are you saying that it is fuel deposits that put carbs out of balance in the first place? Do you not periodically balance your carbs - just clean them?
I think Optimax will be cheaper that the £70 that a local garage quoted me for a balance. I think he was spinning me a yarn.
Rob |
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alexibrow
Settled In Member
United Kingdom
64 Posts |
Posted - 25/03/2008 : 20:17:28
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A tin of Injection Correction costs £12, + P&P, IIRC.
Fuel deposits slowly but surely degrade the performance of your carbs, so before you do any tuning it's wise to remove the sludge first. They may still need a fine tune due to any wear in moving parts, but flushing the crap out will be a big help.
I forgot to mention in my first post; before touching the carbs make sure that everything else is running properly. If I were you, I'd check the spark plug gaps or even put a new set of (correctly gapped) plugs in, if you haven't already. Check that you have a big fat spark at each plug. While you've got the plugs out, do a compression test of each cylinder - it doesn't matter if they're a bit down on the manufacturer's spec, but what is important is that you get similar readings acros all four - any differences of more than, say, 10% and you may have a problem.
Also check that there aren't any air leaks anywhere, as air being introduced via anywhere other than the carb air inlet will put the mixture way off, and all you'll end up doing is tuning the carbs to compensate!
If all seems well, and the exhaust isn't blowing anywhere (could affect the mixture as well) then go ahead and balance the carbies. By doing all this, you're bike should run as well as it did the day it rolled off Honda's production line!
How does the bike run at the moment, BTW? |
It's not karma, its bikema. |
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TektroG
Senior Member
United Kingdom
1009 Posts |
Posted - 25/03/2008 : 23:28:53
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| How do you convert ratios given in the manual for compression to the figure you should be measuring on the gauge? |
I've got 4 words for you sonny: ... |
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rob.onions
New Member
United Kingdom
29 Posts |
Posted - 26/03/2008 : 12:30:18
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Al, the plugs were changed only about 300 miles ago ( after being seriously flooded and not starting for about 2 months.)
To be honest, I've got no real issues with how the bike runs (it doesn't seem to pull quite like it did when I bought it 5 yrs ago - maybe it's psycological and I'm just accustomed to it!)It's just that the milage interval for carb balance is just due. It may be absolutely ok, but if it's easy enough to put a vacuum guage on - I can borrow a set and have a look. |
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gothy
Settled In Member
United Kingdom
52 Posts |
Posted - 26/03/2008 : 17:05:10
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its probably fine, I use super unleaded quite often and their is a major power increase after a few miles.
Also, try riding a fireblade that livens things up a bit if your bored.
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Honda CB400SF 1995. |
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rob.onions
New Member
United Kingdom
29 Posts |
Posted - 26/03/2008 : 22:12:11
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| Buy a Blade and leave the bosom of the 400 crew. Never! The chance would be a fine thing though. |
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gothy
Settled In Member
United Kingdom
52 Posts |
Posted - 26/03/2008 : 22:54:55
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chance? are you young or something?
Hey I have a cb400 and a blade, but it doesn't stop me riding my baby 400.
oh im also 19.
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Honda CB400SF 1995. |
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rob.onions
New Member
United Kingdom
29 Posts |
Posted - 27/03/2008 : 12:46:06
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| Hold on second, I'm sure I had a question at the beginning of this idle banter! Does anyone know how I recognise the vacuum ports on my carbs when I eventually get round to checking them? |
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carb balance
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